/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.volley;

import android.os.Handler;

import java.util.concurrent.Executor;

/**
 * Delivers responses and errors.
 */
public class ExecutorDelivery implements ResponseDelivery {
	/** Used for posting responses, typically to the main thread. */
	private final Executor mResponsePoster;

	/**
	 * Creates a new response delivery interface.
	 * 
	 * @param handler
	 *            {@link Handler} to post responses on
	 */
	public ExecutorDelivery(final Handler handler) {
		// Make an Executor that just wraps the handler.
		mResponsePoster = new Executor() {
			@Override
			public void execute(Runnable command) {
				handler.post(command);
			}
		};
	}

	/**
	 * Creates a new response delivery interface, mockable version for testing.
	 * 
	 * @param executor
	 *            For running delivery tasks
	 */
	public ExecutorDelivery(Executor executor) {
		mResponsePoster = executor;
	}

	@Override
	public void postResponse(Request<?> request, Response<?> response) {
		postResponse(request, response, null);
	}

	@Override
	public void postResponse(Request<?> request, Response<?> response,
			Runnable runnable) {
		request.markDelivered();
		request.addMarker("post-response");
		mResponsePoster.execute(new ResponseDeliveryRunnable(request, response,
				runnable));
	}

	@Override
	public void postError(Request<?> request, VolleyError error) {
		request.addMarker("post-error");
		Response<?> response = Response.error(error);
		mResponsePoster.execute(new ResponseDeliveryRunnable(request, response,
				null));
	}

	/**
	 * A Runnable used for delivering network responses to a listener on the
	 * main thread.
	 */
	@SuppressWarnings("rawtypes")
	private class ResponseDeliveryRunnable implements Runnable {
		private final Request mRequest;
		private final Response mResponse;
		private final Runnable mRunnable;

		public ResponseDeliveryRunnable(Request request, Response response,
				Runnable runnable) {
			mRequest = request;
			mResponse = response;
			mRunnable = runnable;
		}

		@SuppressWarnings("unchecked")
		@Override
		public void run() {
			// If this request has canceled, finish it and don't deliver.
			if (mRequest.isCanceled()) {
				mRequest.finish("canceled-at-delivery");
				return;
			}

			// Deliver a normal response or error, depending.
			if (mResponse.isSuccess()) {
				mRequest.deliverResponse(mResponse.result);
			} else {
				mRequest.deliverError(mResponse.error);
			}

			// If this is an intermediate response, add a marker, otherwise
			// we're done
			// and the request can be finished.
			if (mResponse.intermediate) {
				mRequest.addMarker("intermediate-response");
			} else {
				mRequest.finish("done");
			}

			// If we have been provided a post-delivery runnable, run it.
			if (mRunnable != null) {
				mRunnable.run();
			}
		}
	}
}
